Substituted imidazolium sulfuranes and their use

Abstract

The present invention refers to substituted imidazolium sulfuranes, the use thereof for the transfer of a —CN group or an alkyne group.

The invention claimed is: 
     
       1. An imidazolium sulfurane of the formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         R 1  and R 2  each independently represent hydrogen, alkyl, aralkyl, aryl, heteroaryl, each being optionally substituted by one or more hetero atoms selected from O, N, S or halogen, or R 1  and R 2  may together form a hydrocarbon ring structure, optionally substituted by one or more hetero atoms selected from O, N, S and halogen; 
         R 3  and R 4  each independently represent a lower alkyl group having 1 to 6 carbon atoms, each lower alkyl group being optionally substituted by one or more hetero atoms selected from O, N, S or halogen; 
         X is an anion selected from halogen or a non- or weak-coordinating anion; 
         Y represents a group of the —C≡W formula wherein W represents N, CR 5 , 
       
       
         
           
           
               
               
           
         
       
       or C—CO 2 R 5  wherein R 5  is selected from the group consisting of C 1  to C 20  straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally having one or more unsaturated bonds or C 6  to C 20  aromatic hydrocarbons and partially arene-hydrogenated hydrocarbons, each hydrocarbon optionally being substituted by one or more hetero atoms selected from O, N, S, halogen or a silylgroup;
 with the proviso that compounds of the formula (I) wherein R 1  and R 2  are hydrogen, R 3  and R 4  are methyl, X is halogen and Y is CN are excluded. 
 
     
     
       2. The imidazolium sulfurane of the formula (I) as claimed in  claim 1  wherein:
 R 1  and R 2  each independently represent hydrogen or lower alkyl having 1 to 6 carbon atoms, optionally substituted by one or more hetero atoms selected from O, N, S or halogen, or R 1  and R 2  may together form a 5 to 7 membered hydrocarbon ring structure, optionally substituted by one or more hetero atoms selected from O, N, S or halogen; 
 R 3  and R 4  each independently represent a lower alkyl group having 1 to 6 carbon atoms, each lower alkyl group being optionally substituted by one or more hetero atoms selected from O, N, S or halogen; 
 X is an anion selected from halogen or a non- or weak-coordinating anion; 
 Y represents a group of the formula —C≡W wherein W represents N, CR 5  or C—CO 2 R 5  wherein R 5  is selected from the group consisting of C 1  to C 20  straight chain, branched chain or cyclic aliphatic hydrocarbons, C 3 -C 8 -heterocycloalkyl or C 6  to C 20  aromatic hydrocarbons and partially arene-hydrogenated forms, each hydrocarbon optionally being substituted by one or more hetero atoms selected from O, N, S, halogen or a tri-lower alkyl-silygroup. 
 
     
     
       3. The imidazolium sulfurane of the formula (I) as claimed in  claim 1 , wherein:
 R 1  and R 2  each independently represent hydrogen or lower alkyl having 1 to 6 carbon atoms, optionally substituted by one or more oxygen atoms, or R 1  and R 2  may together form a 5 to 7 membered hydrocarbon ring structure, optionally substituted by one or more oxygen or nitrogen atoms; 
 R 3  and R 4  each independently represent a lower alkyl group selected from methyl, ethyl, propyl, iso-propyl; 
 X is an anion selected from halogen or a non- or weak-coordinating anion; 
 Y represents a group of the —C≡W formula wherein W represents N, CR 5  or C—CO 2 R 5  wherein R 5  is selected from the group consisting of C 1  to C 20  straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally having one or more unsaturated bonds or C 6  to C 20  aromatic hydrocarbons and partially arene-hydrogenated forms, each hydrocarbon optionally being substituted by one or more hetero atoms selected from O, N, S or halogen a tri-lower alkyl-silygroup. 
 
     
     
       4. The imidazolium sulfurane of the formula (I) as claimed in  claim 1 , wherein:
 R 1  and R 2 , R 3  and R 4  and X have the meaning as given in  claim 1  and 
 Y represents a group of the formula: 
 
       
         
           
           
               
               
           
         
         wherein R 5  may be the same or different and may be selected from the group consisting of C 1  to C 20  straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally having one or more unsaturated bonds or C 6  to C 20  aromatic hydrocarbons and partially arene-hydrogenated hydrocarbons, each hydrocarbon optionally being substituted by one or more hetero atoms selected from O, N, S or halogen a tri-lower alkyl-silygroup. 
       
     
     
       5. Process for preparing an imidazolium sulfurane compound of the formula (I): 
       
         
           
           
               
               
           
         
         wherein R 1  and R 2 , R 3  and R 4 , X and Y have the meanings as given in  claim 1 , 
         said process comprising reacting a compound of the formula (II): 
       
       
         
           
           
               
               
           
         
         wherein R 1  to R 4  have the meaning as given in  claim 1 , in a first step, with a halogen to yield a resulting compound, and the resulting compound is reacted in a second step with a compound of the formula R—C≡W, wherein R is a lower alkyl silyl group, wherein the lower alkyl has 1 to 6 carbon atoms. 
       
     
     
       6. Process comprising reacting a compound of the formula (I): 
       
         
           
           
               
               
           
         
         wherein 
         R 1  and R 2  each independently represent hydrogen, alkyl, aralkyl, aryl, heteroaryl, each being optionally substituted by one or more hetero atoms selected from O, N, S or halogen, or R 1  and R 2  may together form a hydrocarbon ring structure, optionally substituted by one or more hetero atoms selected from O, N, S and halogen; 
         R 3  and R 4  each independently represent a lower alkyl group having 1 to 6 carbon atoms, each lower alkyl group being optionally substituted by one or more hetero atoms selected from O, N, S or halogen; 
         X is an anion selected from halogen or a non- or weak-coordinating anion; 
         Y represents a group of the —C≡W formula wherein W represents N, CR 5 , 
       
       
         
           
           
               
               
           
         
       
       or C—CO 2 R 5  wherein R 5  is selected from the group consisting of C 1  to C 20  straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally having one or more unsaturated bonds or C 6  to C 20  aromatic hydrocarbons and partially arene-hydrogenated hydrocarbons, each hydrocarbon optionally being substituted by one or more hetero atoms selected from O, N, S, halogen or a silylgroup;
 with an organic nucleophilic compound R N —H wherein R N  is alkyl, aralkyl, aryl or heteroaryl, each being optionally substituted by one or more hetero atoms selected from O, N, and S, 
 in an organic solvent, and optionally in the presence of a Lewis acid catalyst, resulting in a transfer of the group Y in order to yield a compound of the formula R N —Y. 
 
     
     
       7. Process according to  claim 6 , wherein Y represents —CN, and said reacting is conducted for a direct electrophilic cyanation of a C—H bond in an organic compound. 
     
     
       8. Process according to  claim 6 , wherein W represents CR 5  or C—CO 2 R 5 , and said reacting is conducted for a direct electrophilic alkynylation of a C—H bond in an organic compound. 
     
     
       9. An imidazolium sulfurane of the formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         R 1  and R 2  each independently represent alkyl, aralkyl, aryl, heteroaryl, each being optionally substituted by one or more hetero atoms selected from O, N, S or halogen, or R 1  and R 2  may together form a hydrocarbon ring structure, optionally substituted by one or more hetero atoms selected from O, N, S and halogen; 
         R 3  and R 4  each independently represent a lower alkyl group having 1 to 6 carbon atoms, each lower alkyl group being optionally substituted by one or more hetero atoms selected from O, N, S or halogen; 
         X is an anion selected from halogen or a non- or weak-coordinating anion; 
         Y represents a group of the —C≡W formula wherein W represents N, CR 5 , 
       
       
         
           
           
               
               
           
         
       
       or C—CO 2 R 5  wherein R 5  is selected from the group consisting of C 1  to C 20  straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally having one or more unsaturated bonds or C 6  to C 20  aromatic hydrocarbons and partially arene-hydrogenated hydrocarbons, each hydrocarbon optionally being substituted by one or more hetero atoms selected from O, N, S, halogen or a silylgroup. 
     
     
       10. The imidazolium sulfurane of the formula (I) as claimed in  claim 9 , wherein R 1  and R 2  each independently represent alkyl. 
     
     
       11. Process according to  claim 5 , wherein R—C≡W is trimethylsilyl cyanide. 
     
     
       12. An imidazolium sulfurane of the formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         R 1  and R 2  each independently represent hydrogen, alkyl, aralkyl, aryl, heteroaryl, each being optionally substituted by one or more hetero atoms selected from O, N, S or halogen, or R 1  and R 2  may together form a hydrocarbon ring structure, optionally substituted by one or more hetero atoms selected from O, N, S and halogen; 
         R 3  and R 4  each independently represent a lower alkyl group having 2 to 6 carbon atoms, each lower alkyl group being optionally substituted by one or more hetero atoms selected from O, N, S or halogen; 
         X is an anion selected from halogen or a non- or weak-coordinating anion; 
         Y represents a group of the —C≡W formula wherein W represents N, CR 5 , 
       
       
         
           
           
               
               
           
         
       
       or C—CO 2 R 5  wherein R 5  is selected from the group consisting of C 1  to C 20  straight chain, branched chain or cyclic aliphatic hydrocarbons, optionally having one or more unsaturated bonds or C 6  to C 20  aromatic hydrocarbons and partially arene-hydrogenated hydrocarbons, each hydrocarbon optionally being substituted by one or more hetero atoms selected from O, N, S, halogen or a silylgroup.